A FAQ on various IRC channels I help out on is How vị I vertically center my stuff inside this area? This question is often followed by I"m using vertical-align:middle but it"s not working!

The problem here is three-fold:

HTML layout traditionally was not designed khổng lồ specify vertical behavior. By its very nature, it scales width-wise, and the nội dung flows lớn an appropriate height based on the available width. Traditionally, horizontal sizing and layout is easy; vertical sizing and layout was derived from that.The reason vertical-align:middle isn"t doing what is desired want is because the author doesn"t understand what it"s supposed to do, but …… this is because the CSS specification really screwed this one up (in my opinion)—vertical-align is used to specify two completely different behaviors depending on where it is used.

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vertical-align in table cells

When used in table cells, vertical-align does what most people expect it to, which is mimic the (old, deprecated) valign attribute. In a modern, standards-compliant browser, the following three code snippets vị the same thing:

...

vertical-align on inline elements

When vertical-align is applied lớn inline elements, however, it"s a whole new ballgame. In this situation, it behaves lượt thích the (old, deprecated) align attribute did on

*
and
*
—as examples.

In this paragraph, I have two images—

*
and
*
—as examples.

In this paragraph, I have a xinh tươi little display:inline-blockvertical-align:middle và display:inline-blockvertical-align:text-bottom as an example.


vertical-align on other elements

Technically, this CSS attribute doesn"t go on any other kinds of elements. When the novice developer applies vertical-align khổng lồ normal bloông xã elements (like a standard
) most browsers phối the value to inherit lớn all inline children of that element.

So how do I vertically-center something?!

If you are reading this page, you"re probably not as interested in why what you were doing is wrong. You probably want to lớn know how to lớn vì it properly.

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Method 1

The following example makes two (non-trivial) assumptions. If you can meet these assumptions, then this method is for you:

You can put the nội dung that you want to lớn center inside a block & specify a fixed height for that inner nội dung blochồng.It"s alright khổng lồ absolutely-position this nội dung. (Usually fine, since the parent element inside which the nội dung is centered can still be in flow.

If you can accept the above necessities, the solution is:

Specify the parent container as position:relative sầu or position:absolute.Specify a fixed height on the child container.Set position:absolute và top:một nửa on the child container to move the top down lớn the middle of the parent.Set margin-top:-yy where yy is half the height of the child container khổng lồ offphối the thành tựu up.

An example of this in code:

...
Hey look! I"m vertically centered!

How sweet is this?!


In your browser, the above sầu example renders as:


Hey look! I"m vertically centered!

How sweet is this?!


Method 2

This method requires that you be able to satisfy the following conditions:

You have only a single line of text that you want to center.You can specify a fixed-height for the parent element.

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If you can accept the above sầu necessities, the solution is:

Set the line-height of the parent element khổng lồ the fixed height you want.

An example of this in code:


Chuyên mục: Hỏi Đáp